WO2008058949A2

WO2008058949A2 - Sensor element, device and method for inspecting a printed conductor structure, production method for sensor element

Info

Publication number: WO2008058949A2
Application number: PCT/EP2007/062249
Authority: WO
Inventors: Hagen Klausmann; Karl Kragler
Original assignee: Siemens Aktiengesellschaft
Priority date: 2006-11-16
Filing date: 2007-11-13
Publication date: 2008-05-22
Also published as: WO2008058949A3; CN101432632B; ATE510224T1; EP1987367A2; EP1987367B1; KR20090031665A; KR101028190B1; CN101432632A; JP2009535633A; JP5002007B2

Abstract

The invention relates to a sensor element for inspecting a printed conductor structure (131) that is mounted on a flat support (130). The sensor element (250) comprises a substrate (251), which is mechanically structured in such a way that it has a raised upper region (260) and lowered lower region (280) said planar upper (260) region and lowered lower region (280) being interconnected by a preferably step-type transition region (270). The sensor element (250) also comprises a plurality of sensor electrodes (261), arranged on the planar upper region (260) and a plurality of connecting conductors (471) for electrically connecting the plurality of sensor electrodes (261). A connecting conductor (471) is connected to each sensor electrode (261), said conductor extending from the respective sensor electrode (261) to the lowered lower region (280). The invention also relates to a device and a method for inspecting a printed conductor structure (131), in addition to a production method for the aforementioned sensor element.

Description

description

Sensor element, apparatus and method for inspecting a printed conductor structure, manufacturing method for sensor element

The present invention relates to a sensor element, to a device and to a method for inspecting a printed conductor structure formed on a flat carrier, in particular for contactless inspection of a printed conductor matrix formed on a flat screen substrate. The present invention further relates to a manufacturing method for the above-mentioned sensor element.

In the field of production of liquid crystal displays (LCD, Liquid Crystal Display), an inspection of TFT electrodes (T_hin film T_ransistor electrodes) on a glass substrate is required for an effective and economical production process in order to detect any defects as early as possible in the course of a manufacturing process to recognize for liquid crystal displays.

US Pat. No. 5,974,869 discloses an inspection method for wafers, wherein the surface of wafers is scanned without contact with a metal tip. In this case, the potential difference between the metal tip and the wafer surface is measured, wherein the work function of the electrons from different materials is at this potential difference. As a result, not only different materials but also chemical changes such as corrosion or geometric changes of a surface such as a trench structure can be detected. However, the inspection method has the disadvantage that the surface to be examined has to be rotated relative to the metal tip, so that the inspection method is not suitable for printed conductor structures which are formed on flat carriers. In order to inspect a complex trace matrix, ie a matrix with a large number of pixels in an acceptable time, a high degree of parallelism is required. This means that with a measuring head which has a plurality of sensor electrodes, a plurality of measuring points are scanned or inspected on the printed conductor matrix at the same time.

For example, on a modern 20-inch computer screen with a resolution of 1600 x 1200 pixels, there are 5.76 million pixels. In this case, three subpixels are required per pixel to allow in a known manner by color mixing a colored display. The pixels typically have distances of about 50μm (cell phone or camcorder displays) up to 500μm (large scale LCD-TV).

When parallelizing the track inspection, it must be ensured that the individual sensor electrodes used are geometrically within a few μm in a plane plane due to the strong distance dependence, in particular of capacitive measuring methods. If this condition is fulfilled, then a multi-channel sensor can be routed at intervals of a few μm over a TFT conductor track matrix to be inspected.

The invention has for its object to provide a sensor element and a device for inspection of a formed on a flat carrier track structure, which can be produced in a relatively simple manner and which allow a precise multi-channel measurement with arranged in a plane sensor electrodes. Of the

A further object of the invention is to provide a measuring method for inspecting a printed conductor structure formed on a flat carrier, with which even complex printed conductor structures for liquid crystal displays with a large number of pixels can be inspected in an acceptable time. In addition, the invention has the object to provide a particularly advantageous manufacturing method for at least one sensor element mentioned.

These objects are achieved by the subject-matter of the independent patent claims. Advantageous embodiments of the present invention are described in the dependent claims.

Independent claim 1 describes a sensor element for inspection of a printed conductor structure formed on a flat carrier. The described sensor element is particularly suitable for contactless inspection of a printed conductor matrix formed on a flat screen substrate. The sensor element comprises (a) a substrate mechanically structured to have a raised upper portion and a recessed lower portion, wherein the planar upper portion and the recessed lower portion are interconnected by a transition region, (b) a A plurality of sensor electrodes formed on the planar upper portion, and (c) a plurality of connecting lines for electrically contacting the plurality of sensor electrodes. In this case, each sensor electrode is assigned a connecting line which extends from the respective sensor electrode to the recessed lower area.

The cited sensor element is based on the knowledge that, when using a step-like substrate, wirings which are required for electrical contacting of the individual sensor electrodes can be guided in a space-saving manner from the upper region, which comprises the sensor electrodes, in the lower region. Thus, a compact multi-channel sensor element can be realized, wherein each sensor electrode defines a separate measurement channel. Preferably, 2 n high sensor elements are used, where n is an integer. Thus, in a space-saving manner, for example, a 2-, 4-, 8-, 16-, 32-, 64-, 128-, 256-, 512-, 1028-channel sensor element can be realized.

The realized by the step arrangement of the substrate individual contacting of all sensor electrodes allows individual control of individual sensor electrodes. Thus, the sensor element described can be used in a variety of ways, since a measurement with only one, with several or with all of the planar region formed sensor electrodes is possible.

The sensor element described is particularly suitable for the inspection of semi-finished flat-screen substrates, which have a plurality of thin-film transistors in a conductor matrix. The inspection can be done by a

Inspection method are carried out, in which (a) by means of a positioning the sensor element and thus the sensor electrodes is positioned relative to the conductor track structure at a predetermined distance, (b) between the sensor electrodes and the conductor track structure, an electrical voltage is applied, (c) the sensor electrodes correspondingly driving the positioning means relative to the flat panel substrate in a plane parallel to the flat panel substrate, (d) measuring a current flow through at least one electrical lead connected to a sensor electrode, and (e) from the magnitude of the current flow, the local voltage condition of the trace structure is detected in the subregion.

According to an embodiment of the invention according to claim 2, the raised upper portion has a planar surface. This has the advantage that assuming an identical shape of all sensor electrodes, the tips of all sensor electrodes are virtually automatically located within a plane. In a parallel orientation of the sensor element to the conductor track structure to be inspected, a plurality of measuring points can thus be scanned simultaneously, wherein for each sensor electrode, the same measuring distance between conductor track structure and electrode tip is given.

The term planar is to be understood below as meaning a flatness in which the upper region has height or thickness fluctuations of at most ± 2 μm, preferably of at most ± 1 μm and in particular of not more than ± 0.5 μm. Of course, the required planarity depends on the particular measurement task and in particular on the required accuracy or sensitivity of the measurement signals.

According to a further embodiment of the invention according to claim 3, the sensor electrodes and / or the connecting lines are manufactured by means of thin-film and / or microstructuring technology. This has the advantage that the individual sensor electrodes can be produced together by means of method steps known, for example, from semiconductor technology, which enable a uniform and precise shaping of the individual sensor electrodes. The term microstructuring technique is understood to mean, for example, microlithographic methods which are used in particular in the field of the production of semiconductor components or of micromechanical components. By using microlithographic methods, a multiplicity of different sensor elements can be produced reproducibly and with constant high precision.

Preferably, the sensor electrodes and / or the connection lines are formed on a mechanically prestructured substrate, in which the recessed lower region has been formed, for example, by grinding or by hot deformation. Thus, the raised upper portion of the substrate can remain substantially untreated, so that with a correspondingly high original surface quality of the substrate, a high planarity of the upper region or of the individual sensor electrodes is automatically ensured. According to claim 4, the sensor element in addition to a shield, which is designed such that an electromagnetic radiation from the connecting lines and / or an electromagnetic radiation is at least reduced in the connecting lines. The shield preferably has a metallic layer, which can likewise be applied to the described sensor element by means of thin-film technology.

According to claim 5, the substrate is a thin glass. The use of thin glass has the advantage that pre-structuring of the step-like sensor element can be carried out in a simple manner, for example by means of known precision grinding processes. Especially suitable for this

Application described sensor element has borosilicate glass Schott AG, Hattenbergstr. 10, D-55122 Mainz. The use of thin glass as a starting material also has the advantage that a particularly high planarity with height or thickness fluctuations of at most + - 0.5 microns can be realized in a simple manner.

According to claim 6, the substrate is a wafer, in particular a silicon wafer. This has the advantage that a substrate material which is precisely known from semiconductor technology and for the handling and processing of which a multiplicity of suitable procedures are known is used for the production of the described sensor element. In order to produce a corresponding pre-structuring which has at least one step or at least one depression, in particular wet-chemical etching processes are suitable. However, dry etching methods can also be used.

According to claim 7, the sensor element additionally has a plurality of electrical connection surfaces to the other

Contacting the sensor element, which pads are formed on the recessed lower portion, wherein each associated with a pad of a sensor electrode and is electrically connected to the corresponding connecting line.

Preferably, the pads are suitable to form so-called. Bond connections. This has the advantage that the individual sensor electrodes can be contacted effectively with a flexible printed circuit board, for example by means of an ACF (Anisotropic Conductive Film Bonding) bonding process. In this case, all bond connections including the flexible printed circuit board can be realized so flat that even with a very small depression of the lower region compared to the upper region of for example 200 microns, the flexible printed circuit board does not protrude beyond the sensor electrodes, so that the tips of the Sensor electrodes represent the most elevated areas of the sensor element described.

Instead of areal bonding techniques, the so-called wire-bonding can also be used for further contacting of the sensor element. Since the wire-bonding, for example, from the IC connection technology is well known, can be used for producing the sensor element described in an advantageous manner to known methods for electrical contacting.

According to claim 8, the sensor element in addition to a flexible printed circuit board, which comprises a plurality of drive lines, wherein in each case a drive line is connected to an electrical connection surface. The use of so-called. Flexwire has the advantage that the sensor element described can be contacted in a simple and reliable manner. In addition, the sensor element can be installed in various measuring devices, which are optionally optimized for different measurement tasks. Thus, the sensor element described can be used universally. According to claim 9, the flexible printed circuit board on at least a flat shield, so that a shield of the connecting lines to the flexible printed circuit board or to the Flexwire can be continued.

According to claim 10, the transition between the transition region and the raised upper region and / or the transition between the transition region and the recessed lower region takes place at a shallow angle. In this context, the term "flat" means that the corresponding transition angle is less than 90 °. This has the advantage that the application of the connecting lines is facilitated because the connecting lines do not have to be formed around a sharp corner. The transition angle is preferably considerably less than 90 °, for example 5 °.

It should be noted at this point that the transition can also take place free of edges, for example with rounded quasi-continuous transitions.

According to claim 11, the sensor electrodes are arranged in a row. In addition to a particularly simple realization, this has the advantage that the sensor element described represents a linear sensor line in which the individual sensor electrodes are preferably spaced apart equidistant from one another. By means of a linear movement of the sensor element relative to a substrate to be inspected, it is thus possible to scan a measuring surface which depends on the width or, for a given sensor electrode distance, on the number of sensor electrodes.

It should be noted at this point that the sensor electrodes can also be arranged offset from each other in at least two rows. This has the advantage that the described sensor element can be adapted to different measuring tasks. In particular, an adaptation to different pitches (so-called pitch distances) of thin-film transistors possible, which may be formed or arranged on substrates of liquid crystal flat screens.

Independent claim 12 describes a device for inspection of a printed conductor structure formed on a flat carrier. The device described is particularly suitable for contactless inspection of a formed on a flat screen substrate

Interconnect matrix. The device comprises (a) a chassis, (b) a receiving element which is arranged on the chassis and which is adapted to receive the flat carrier, (c) at least one sensor element according to one of the embodiments described above for inspecting the printed conductor structure and ( d) a positioning system, which is arranged on the chassis and which is coupled to the sensor element and / or with the receiving element such that the sensor element can be positioned relative to the flat carrier in a plane parallel to the conductor track structure.

The above-mentioned inspection device is based on the finding that the sensor element described above can be moved by means of a conventional precision positioning device relative to a conductor track structure to be inspected and thus flat scanning of the track structure can be realized in a simple manner. Such precision positioning devices are known, in particular, from the field of electronics manufacturing, so that it is possible to resort to known standard components for realizing the inspection device. The said inspection device can thus be manufactured comparatively inexpensively.

The positioning system may be a so-called surface positioning system, which enables a two-dimensional movement of the sensor element relative to the planar carrier. In this case, both a two-dimensional positioning of the carrier and a two-dimensional positioning of the sensor element can take place.

The positioning system can also be configured such that the carrier is movable along a first direction and the sensor element along a second direction, which second direction is oriented at an angle, preferably perpendicular, to the first direction. In this way, by a combination of two linear movements, a precise complete scanning of a two-dimensional printed conductor structure can be realized. This also applies if the surface of the conductor track structure is so large that a complete scanning is not possible by a merely one-dimensional movement of the sensor element along a direction which direction is preferably oriented perpendicular to a sensor line defined by juxtaposed sensor electrodes.

Of course, only a one-dimensional positioning of the sensor element can take place relative to the carrier. In this case too, a planar scanning of the printed conductor structure can be realized if a sensor element with an elongate measuring line is used or if several sensor elements are used at the same time.

According to an embodiment of the invention according to claim 13, the device additionally has an evaluation unit, which is connected downstream of the sensor element and which is set up to evaluate the measurement signals provided by the sensor element.

The evaluation unit is configured, for example, to evaluate the local stress state of a subarea of the interconnect structure for determining the quality of the same. The term quality of the conductor track structure in this context, in particular the areal geometric Dimensions of the conductor track structure to understand. These include in particular defects such as short circuits, constrictions or broken lines. Such defects definitely change the local stress distribution and can thus be reliably detected.

However, the quality of the printed conductor structure is also determined by dielectric influences which influence the capacitance between the respective sensor electrode and the printed conductor structure. This happens, for example, by chemical changes in the conductor track structure or by undesired dielectric deposits on the printed conductor structure.

With independent claim 14, a method for

Inspection of a formed on a flat carrier track structure described. The described method is particularly suitable for contactless inspection of a printed circuit board matrix formed on a flat-screen substrate. The method comprises the following steps: (a) positioning the sensor element according to an embodiment described above by means of a positioning system relative to the printed conductor structure at a predetermined measuring distance, (b) applying an electrical voltage between the sensor electrodes and the printed conductor structure, (c) moving the sensor element Sensor element by a corresponding control of the positioning system relative to the planar carrier in a plane parallel to the conductor track structure, (d) measuring a current flow through at least one connected to a sensor electrode connecting line and (e) detecting a local stress state in at least a portion of the conductor track structure.

The method described is based on the knowledge that the distribution and the course of the electric field lines between the individual sensor electrodes and the respective scanning subregions of the conductor track structure of the depend on local stress state. The course of the electric field lines determines the electrical capacitance between the sensor electrode and the scanning subregion. With a variation of the field line distribution, the capacitance between the sensor electrode and the scanning subarea of the conductor track structure also changes, so that the current flow I between the respective sensor electrode and the conductor track structure results from the following equation:

I = (U _AC + U _DC ) dC / dt + C dU _AC / dt

In this case, U _A c is an AC voltage and U _D c is a DC voltage, which lie between the respective sensor electrode and the conductor track structure. C is the capacitance between sensor electrode and interconnect structure. The term d / dt denotes the time derivative of the variables C and U _A c. The current flow I also flows through the connecting line assigned to the respective sensor electrode and can be detected by correspondingly sensitive current measuring devices.

It should be noted that for the realization of the invention, only a relative positioning between the conductor track and sensor element is required. This means that either the sensor element, the flat carrier or even the sensor element and the carrier can be moved by means of at least one positioning system.

The method described has the advantage that the local stress state of the conductor track structure can be measured in comparison to known inspection methods with a simple and comparatively cheap detection electronics. Thus, the contactless inspection method can be carried out with a device which contains electrical and mechanical components that are offered by many different manufacturers and therefore can be purchased comparatively cheap. According to an embodiment of the invention according to claim 15, the conductor track structure is scanned by a grid-shaped movement of the sensor element. This has the advantage that a matrix-like arrangement of conductor track structures can be measured quickly in the context of a standardized scanning process. In this case, the sensor element can be guided, for example, in a meandering movement over the conductor track structure to be inspected. The relative movement between see sensor element and carrier is preferably carried out continuously. However, the relative movement can equally well take the form of a stepwise movement.

According to a further embodiment of the invention according to claim 16, an amplitude-modulated voltage is applied between the sensor electrodes and the printed conductor structure. This allows a particularly sensitive inspection, so that almost all defects of a conductor track structure can be reliably detected.

Independent claim 17 specifies a production method for at least one sensor element for inspection of a printed conductor structure formed on a flat carrier. The manufacturing method comprises the following steps: (a) producing at least one trench structure in a starting substrate so that a raised upper surface area and a recessed lower area area are formed in the starting substrate, which are interconnected via a transitional intermediate area, (b) forming (c) forming the plurality of connection lines, wherein each sensor electrode is associated with a connection line extending from the respective sensor electrode to the recessed lower surface area, and (d) singulating the starting substrate such that at least one sensor element is cut out according to an embodiment described above. Here is the raised upper portion of the Sensor element associated with the raised upper surface area of the starting substrate. Further, the recessed lower portion of the sensor element is associated with the recessed lower surface area of the starting substrate. In addition, the transition region of the sensor element is assigned to the transitional intermediate region of the starting substrate.

The production method described is based on the knowledge that at the same time a plurality of the above-described sensor elements can be produced by a common processing of a common starting substrate, wherein after a corresponding formation of all sensor electrodes and connecting lines the starting substrate is separated in a suitable manner. The starting substrate may be a glass substrate, for example a silicate glass, or a wafer, for example made of silicon. The formation of the sensor electrodes and connecting lines preferably takes place by means of known lithographic or photolithographic methods.

According to an embodiment of the invention according to claim 18, the manufacturing method additionally comprises the following step: forming lateral shields extending from the raised upper surface area to the recessed lower surface area, wherein a lateral shield is arranged next to a connecting line.

With a corresponding contacting of the lateral shielding, preferably with a grounding of the lateral shields, an electromagnetic radiation from the connecting lines and / or an electromagnetic radiation into the connecting lines can thus be considerably reduced during the operation of correspondingly produced sensor elements. In this way, the sensitivity and the

Reliability of the sensor elements can be significantly increased. The lateral shields can be realized by a thin metallic layer, for example by a correspondingly structured aluminum layer. Coating thicknesses in the range of 200 to 500 nm have proved favorable. In addition to aluminum, it is also possible to use alloys of aluminum, for example with copper (AlCu), but also chromium and chromium alloys.

According to a further embodiment of the invention according to claim 19, the manufacturing method additionally comprises the following steps: (a) applying a first metallization layer and exposing the connection lines, (b) applying an insulating layer, (c) exposing the sensor electrodes and the lateral shields from the isolate depositing a second metallization layer such that the lateral shields and the second metallization layer are electrically conductively connected to one another, and (e) exposing the sensor electrodes from the second metallization layer. This has the advantage that with the second metallization layer a full-surface

Shielding electrode is generated, which further reduces the electromagnetic sensitivity of the sensor elements produced by the described manufacturing method.

The insulating layer may be, for example, a silicon nitride layer. Again, a layer thickness in the range of 200 to 800 nm has proved to be favorable. It should be noted that the insulating layer can also consist of silicon dioxide or silicon oxynitride. The exposure of the sensor electrodes and the lateral shields preferably takes place by means of a suitable lithographic procedure. For example, the first and / or the second metallization layer may again be an aluminum layer in the range from 200 to 500 nm. This corresponds to the above-mentioned layer for producing the lateral shields. Again, other metallizations, such as AlCu or Cr are conceivable. It should be noted that, in a corresponding manner, a lower metallization layer can also be formed on the starting substrate prior to the formation of the connecting lines, wherein the lower metallization layer is electrically separated from the connecting lines by means of a further insulating layer. Thus, by a suitable connection of this lower metallization layer with the lateral shields and the said upper metallization layer, a shield electrode is produced which completely surrounds the connection lines. This contributes to an even better shielding of the connecting lines.

According to claim 20, the manufacturing method additionally comprises the following step: contacting the connection lines by means of a flexible printed circuit board. In this case, the further contacting of the connecting lines preferably takes place after the individual sensor elements have been separated from the common starting substrate.

The contacting by means of a flexible printed circuit board has the advantage that each individual sensor element can be contacted in a simple and at the same time reliable manner. In addition, the sensor element can be installed in optionally optimized with regard to different measurement tasks measuring devices, so that the sensor element described is universally applicable.

The contacting of the flexible printed circuit board to the connecting lines can take place via a plurality of electrical connecting surfaces, which are formed on the lower region. In each case, a connection surface is assigned to a sensor electrode and electrically connected to the corresponding connection line. The formation of the pads can be suitably combined with the manufacturing steps described above. As already explained above, the connection surfaces are suitable for forming so-called bond connections. This has the advantage that the individual sensor electrodes can be contacted in an effective manner, for example by means of a flat bonding process or by means of wire bonding with a flexible printed circuit board.

According to claim 21, a plurality of sensor elements to be manufactured are placed in the starting substrate such that (a) some sensor elements adjacent to each other are arranged in a row parallel to a longitudinal axis of the trench structure and / or (b) some sensor elements with respect to a longitudinal axis of the trench structure are arranged opposite each other on different sides.

This has the advantage that the individual sensor elements are arranged in the benefit of the starting substrate in an effective and space-saving manner. Each sensor element thus has an upper part of the raised upper surface area of the starting substrate and a lower part of the recessed lower area of the starting substrate. As described above in connection with the sensor element according to the invention, the sensor electrodes are integrally formed on the upper part, whereas the lower part is used for contacting the respective sensor element.

The manufacturing method described also has the advantage that a large number of individual sensor elements can be produced in an effective manner via the layout and the size of the starting substrate.

Of course, a plurality of trenches can also be formed in a starting substrate, which are preferably oriented parallel to one another. In this way, a flat starting substrate can be used almost completely for producing the sensor elements according to the invention. Further advantages and features of the present invention will become apparent from the following exemplary description of presently preferred embodiments. In the drawing show in schematic representations:

Figure 1 is a perspective view of an inspection ^¬ device for contactless inspection of a flat panel display formed on a substrate conductor matrix,

2a shows a multi-channel sensor element in a perspektivi ^¬ rule representation,

FIG. 2b shows the multi-channel sensor element shown in FIG. 2a in a plan view,

Figure 3a is a pre-structured starting substrate for the manufacture ^¬ averaging a plurality of multi-channel sensor elements in a plan view,

FIG. 3 b shows the starting substrate shown in FIG. 3 a in a cross-sectional view,

FIG. 3c shows a spatial arrangement of a plurality of multichannel sensor elements to be produced on the starting substrate shown in FIG. 3a,

Figure 4a is an intermediate in the manufacture of a multi-channel sensor element in a plan view, are formed on the sensor substrate by a first metallization ^¬ approximately planar sensor electrodes, interconnections, pads and shields,

4b, the intermediate product shown in Figure 4a in a perspective view, FIG. 4c shows an enlarged view of the sensor electrodes, the connecting lines and a shield of the intermediate product shown in FIG. 4a,

5a shows a manufactured multi-channel sensor element in a plan view,

5b shows the multi-channel sensor element shown in FIG. 5a in a perspective view,

6a shows a contacted with a flexible printed circuit board multi-channel sensor element in a perspective view and

6b, the multi-channel sensor element shown in Figure 6a in a cross-sectional view.

It should be noted at this point that in the drawing the reference signs of identical or mutually corresponding components differ only in their first digit.

FIG. 1 shows an inspection device 100 for contactless inspection of a printed conductor structure 131 formed on a flat carrier 130. According to the exemplary embodiment shown here, the planar carrier is a flat-screen substrate 130 on which, after an early production step, for the production of an LCD flat screen a trace matrix 131 has been formed, by means of which a plurality of thin-film transistors are contacted.

The inspection device 100 has a frame or a chassis 101, on which a receiving element 102 is arranged. The receiving element 102, which according to the embodiment illustrated here is a fixing table 102, serves to receive the flat-screen substrate 130. On the chassis 101, two parallel aligned guides 103 are attached. The two guides 103 carry a transverse support arm 104. The transverse support arm 104 has a guide 105 on which a support member 106 is slidably mounted. The two guides 103 extend along a y-direction, the guide 105 runs along an x-direction.

On the carrier element 106, a multi-channel sensor element 150 is arranged, which has a plurality of sensor electrodes, not shown. The guides 103, the carrier arm 104, the guide 105 and the carrier element 106 together constitute a surface positioning system not shown drive motors. By a corresponding control of the drive motors, the multi-channel sensor element 150 can be positioned parallel to the flat panel substrate 130. In this case, a certain predetermined measuring distance of a few 10 μm is always maintained between the sensor electrodes and the printed conductor matrix.

FIG. 2 a shows the multi-channel sensor element 150 used for the inspection device 100, which is now provided with the reference numeral 250. The multi-channel sensor element 250 has a stepped substrate 251, which has been prestructured, for example, starting from a thin glass or a wafer. As a result, the sensor element 250 has a raised upper area 260 and a recessed lower area 280, which are connected to one another via a stepped transition area 270.

The raised upper portion 260 is provided with a plurality of sensor electrodes 261 arranged along a row. The raised upper area 260 has a very high planarity, wherein the height variations of the surface 262 of the area 260 only reach a maximum unevenness of ± 0.5 μm. This means that, an identical Assuming table shape of all sensor electrodes, the tips of all sensor electrodes 261 are virtually automatically located within a plane.

The recessed lower portion 280 is provided with a plurality of lands 281. Each connection surface 281 is connected to one of the sensor electrodes 261 by means of a connecting line which is hidden by a cover layer and thus not shown.

As can be seen in FIG. 2a, the step formed by the intermediate region 270 has a very shallow angle. This angle is approximately 5 ° according to the embodiment shown here. This has the advantage that the connecting lines are guided only over a largely edge-free flat transition, so that in the manufacture of the connecting lines, which production preferably can be done by means of known lithographic process, line interruptions are difficult to get.

FIG. 2b shows the multi-channel sensor element 250 in a plan view. According to the exemplary embodiment illustrated here, the multi-channel sensor element 250 has a total of 64 sensor electrodes 261. Parallel to the row of sensor elements 261, the sensor element 250 has a length of 12 mm along an x-direction. The sensor element 250 further has a width of 10 mm perpendicular to the row of the sensor elements 261 along a y-direction, wherein the raised upper portion 260 has a width of 4 mm, the intermediate portion 270 a width of 2.3 mm and the recessed lower Region 280 has a width of 3.7 mm. Of course, other spatial dimensions of the multi-channel sensor element 250 are possible.

In the raised upper portion 260, four centering marks 252 are also present, which is in the manufacture of the multi-channel sensor element 250 of importance. These Production will be described in more detail below. The centering markings 252 serve, for example, for an exact spatial assignment of masks for structuring steps in the production of sensor electrodes, connecting lines and connection surfaces.

In the recessed lower portion 280 64 pads 281 are formed. Each pad 281 is connected via a connecting line, not shown, with a specific sensor electrode 261. In this case, the connection lines are each provided with a shield which can be contacted together via ground connection surfaces 282. The exact form of the shield is explained below with reference to Figure 4c in detail.

In the following, a preferred manufacturing method for one or a plurality of multi-channel sensor elements will be described with reference to FIGS. 3 to 6. In this case, further structural details of the multichannel sensor element 250 described above are explained.

FIG. 3 a shows a plan view of a prestructured starting substrate 390 for producing a plurality of multi-channel sensor elements. The pre-structuring, which can take place by means of mechanical grinding and / or an etching process, forms a trench structure 391 in the starting substrate 390. The trench structure has a plurality of spaced-apart recessed lower surface areas 391. The recessed lower surface regions 391 extend along an x-direction. A recessed lower surface area 391 is perpendicular to its longitudinal extent, ie, along a y-direction via a transitional intermediate portion 393 in a raised upper surface area 392 over. According to the exemplary embodiment illustrated here, the recessed lower surface regions 391 and the raised upper surface regions 392 extend parallel to one another. However, other trench structures, for example a meandering trench structure, are also conceivable.

FIG. 3b shows the starting substrate 390 in a cross-sectional view perpendicular to the x-direction. The outer raised upper surface areas at the edge of the starting substrate 390 have a width of about 13 mm along the y-direction. The inner raised upper surface areas have a width of 8.3 mm. The recessed lower surface portions 391 have a width of 7.7 mm and the two adjacent transition intermediate portions 393 have a width of about 2.3 mm. The transitional intermediate regions 393 are inclined at an angle of approximately 5 ° relative to the surface of the raised upper surface regions 391. The height difference along the z-direction between the raised upper surface portions 391 and the recessed lower surface portions 391 is about 200 μm. Of course, other geometric dimensions are conceivable to produce a multi-channel sensor elements, as explained in the following.

FIG. 3c shows the arrangement of a multiplicity of multichannel sensor elements 350 to be produced on the starting substrate

390. The individual sensor elements 350 are arranged adjacent to one another in a plurality of rows parallel to the x-direction. Furthermore, sensor elements 350, which are assigned to two adjacent rows, are arranged opposite one another. Each sensor element 350 thus has an upper part of the raised upper surface area 392 of the starting substrate 390 and a lower part of the recessed lower surface area 391 of the starting substrate 390.

The sensor electrodes are subsequently formed on the upper part, whereas the lower part is used for contacting the respective sensor element 350. this has the advantage that the individual sensor elements 350 are arranged in the benefit of the starting substrate 390 in an effective and space-saving manner. Thus, by proper choice of layout and size of the starting substrate 390, a large number of individual sensor elements 350 can be effectively manufactured.

FIGS. 4a and 4b show an intermediate product in the production of a multichannel sensor element 450. FIG. 4a shows this intermediate product in a plan view, FIG. 4b shows the intermediate product in a perspective view.

The intermediate product has a first metallization plane which has been applied to the sensor substrate 451 and patterned in a known manner, for example by means of lithography. The patterning defines (a) sensor electrodes 461 in the raised top region 460, (b) in the recessed bottom region 480

481 defines and (c) in the step-like transitional region 470 connecting lines 471 defined. In this case, the connecting lines 471 extend along the y-direction on one side to the sensor electrodes 461 and on the other side to the pads 481. In addition, lateral shields 475 are defined, which are formed in the same stepped plane as the connecting lines 471 , The lateral shields are electrically conductively connected to each other and can via grounding pads

482 be contacted.

FIG. 4c shows an enlarged view of the sensor electrodes 461, which are contacted by the connecting lines 471 and shielded from the electromagnetic radiation by the lateral shields 475.

FIGS. 5a and 5b show the finished multichannel sensor element 550. FIG. 5a shows the multichannel sensor element 550. FIG. element 550 in a plan view, Figure 5b shows the multi-channel sensor element 550 in a perspective view.

Starting from the intermediate product shown in FIGS. 4a and 4b, the finished multi-channel sensor element 550 was produced by the following method steps:

1. Application and structuring of the first metallization layer (aluminum)

2. Application of an insulating plane, for example a silicon nitride layer, and structuring of the applied insulating plane, so that the sensor electrodes 561, the lateral shields and the connection surfaces 581 are exposed.

3. Application of a further metallization plane 578, for example aluminum, and structuring of the further metallization plane 578, for example by photolithography, so that the sensor electrodes 561 and the pads 581 are exposed again.

In this way, a full-surface shielding electrode for the connecting lines is generated by the further metallization level 578. As a result, the raised upper area of the substrate 551 thus constitutes a sensor field 560, which has a total of 64 sensor electrodes 561 arranged in a row, which are connected to a corresponding connection area 581 via a respective shielded connection line. The connection surfaces 581 are located in the recessed lower region, which is therefore also referred to as the connection region 580 of the sensor element 550. The connection lines extend over the transition region 570.

FIGS. 6a and 6b show a multichannel sensor element 650 contacted with a flexible printed circuit board 685. FIG. 6 a shows a top view, FIG. 6 b shows a perspective view of the contacted multichannel sensor element 650.

The flexible printed circuit board or Flexwire 685 is so flat that even with the only very small depression of the lower region 680 compared to the upper region 660 of 200 μm, the flexible printed circuit board 685 does not protrude beyond the sensor electrodes. This means that the tips of the sensor electrodes represent the most elevated portions of the multi-channel sensor element 650.

The flexible printed circuit board 685 is contacted, for example, by means of an ACF (Anisotropic Conductive Film Bonding) bonding process with the corresponding connection surfaces. Of course, the flexible printed circuit board 685 can also be contacted to the connection surfaces by means of conventional wire bonding.

It should be noted that the embodiments described herein represent only a limited selection of possible embodiments of the invention. Thus, it is possible to combine the features of individual embodiments in a suitable manner with one another, so that for the person skilled in the art with the variants of embodiment which are explicit here, a

Variety of different embodiments are to be regarded as obviously disclosed.

LIST OF REFERENCE NUMBERS

100 inspection device

101 chassis 102 receiving element / fixing table

103 tours (y-guides)

104 transverse support arm

105 leadership (x-leadership)

106 carrier element 110 evaluation unit

130 flat carrier / flat screen substrate

131 Conductor Structure / Conductor Matrix 150 Sensor element

250 multi-channel sensor element

251 substrate / thin glass / wafer

252 centering marks

260 raised upper area / sensor field

261 sensor electrodes 262 plane surface

270 transition area / step

280 recessed lower area / connection area

281 connection surfaces

282 ground pads

350 multi-channel sensor element

390 starting substrate

391 trench structure / recessed lower surface areas

392 raised upper surface areas 393 Transitional intermediate area

450 multi-channel sensor element

451 substrate / thin glass / wafer

460 raised upper area / sensor field 461 sensor electrodes

470 Transition Range / Level

471 connecting lines 475 shielding

480 recessed lower area / connection area

481 connection surfaces

482 ground pads

550 multi-channel sensor element

551 substrate / thin glass / wafer

560 raised upper area / sensor field

561 sensor electrodes 570 transition area / step

578 metallization layer

580 recessed lower area / connection area

581 connection surfaces

582 ground pads

650 multi-channel sensor element

651 substrate / thin glass / wafer

660 raised upper area / sensor field

670 transition area / step 680 recessed lower area / connection area

685 flexible printed circuit board / Flexwire

Claims

claims

A sensor element for inspecting a printed conductor structure (131) formed on a planar carrier (130), in particular for contactless inspection of a printed conductor matrix (131) formed on a flat screen substrate (130), the sensor element (150, 250, 350 , 450, 550, 650)

A substrate (251, 451, 551, 651) mechanically structured to have a raised top

Area (260, 360, 460, 560, 660) and a recessed lower portion (280, 380, 480, 580, 680), wherein the planar upper portion (260, 360, 460, 560, 660) and the recessed lower Area (280, 380, 480, 580, 680) by a transition region (270, 370, 470, 570, 670) are interconnected,

• a plurality of sensor electrodes (261, 461, 561) formed on the planar upper portion (260, 360, 460, 560, 660), and • a plurality of connecting leads (471) for electrically contacting the plurality of sensor electrodes (47) 261, 461, 561), each sensor electrode (261, 461, 561) being associated with a connecting line (471) extending from the respective sensor electrode (261, 461, 561) to the recessed lower area (280, 380, 480, 580, 680).

2. Sensor element according to claim 1, wherein the raised upper portion (260, 360, 460, 560, 660) has a planar surface (262).

3. Sensor element according to one of claims 1 to 2, wherein the sensor electrodes (261, 461, 561) and / or the connecting lines (471) are made by means of thin-film and / or micro-structuring technology.

4. Sensor element according to one of claims 1 to 3, additionally comprising

• A shield (475), which is designed such that an electromagnetic radiation from the connecting lines (471) and / or an electromagnetic radiation in the connecting lines (471) is at least reduced.

5. Sensor element according to one of claims 1 to 4, wherein the substrate is a thin glass (251, 451, 551, 651).

6. Sensor element according to one of claims 1 to 4, wherein the substrate is a wafer, in particular a silicon wafer.

7. Sensor element according to one of claims 1 to 6, additionally comprising

• a plurality of electrical connection surfaces (281, 481, 581) for further contacting of the sensor element (150, 250, 350, 450, 550, 650), which connection surfaces (281, 481, 581) at the recessed lower portion (280, 380 , 480, 580, 680), wherein in each case one connection surface (281, 481, 581) is assigned to a sensor electrode (261, 461, 561) and is electrically connected to the corresponding connection line (471).

8. Sensor element according to claim 7, additionally comprising

• A flexible printed circuit board (685) having a plurality of drive lines, wherein in each case a drive line to an electrical connection surface (281, 481, 581) is connected.

9. Sensor element according to claim 8, wherein the flexible printed circuit board (685) at least one planar

Shielding has.

10. Sensor element according to one of claims 1 to 9, wherein the transition between the transition region (270, 370, 470, 570, 670) and the raised upper region (260, 360, 460, 560, 660) and / or

the transition between the transition region (270, 370, 470, 570, 670) and the recessed lower region (280, 380, 480,

580, 680) at a shallow angle.

11. Sensor element according to one of claims 1 to 10, wherein the sensor electrodes (261, 461, 561) are arranged in a row.

12. An apparatus for inspecting a printed conductor structure (131) formed on a flat carrier (130), in particular for contactless inspection of a printed conductor matrix (131) formed on a flat screen substrate (130), comprising the device

A chassis (101),

A receiving element (102), which is arranged on the chassis (101) and which is adapted to receive the planar carrier (130),

At least one sensor element (150, 250, 350, 450, 550, 650) according to one of claims 1 to 10 for inspecting the printed conductor structure (131) and a positioning system (103, 104, 105, 106) attached to the chassis ( 101) and which is coupled to the sensor element (150, 250, 350, 450, 550, 650) and / or to the receiving element (102) in such a way that the sensor element (150, 250, 350, 450, 550, 650 ) is positionable relative to the flat carrier (130) in a plane parallel to the track structure (131).

13. The apparatus of claim 12, further comprising

• an evaluation unit (110), which is the sensor element (150, 250, 350, 450, 550, 650) connected downstream and which for

Evaluation of the provided by the sensor element (150, 250, 350, 450, 550, 650) measuring signals is set up.

14. A method for inspection of a printed conductor structure formed on a flat carrier, in particular for contactless inspection of a printed conductor matrix formed on a flat screen substrate, the method comprising the following steps:

Positioning the sensor element (150, 250, 350, 450, 550, 650) according to one of claims 1 to 10 by means of a positioning system (103, 104, 105, 106) relative to the printed conductor structure (131) at a predetermined measuring distance,

• Applying an electrical voltage between the sensor electrodes (261, 461, 561) and the conductor track structure

(131)

Moving the sensor element (150, 250, 350, 450, 550, 650) by a corresponding activation of the positioning system (103, 104, 105, 106) relative to the planar support (130) in a plane parallel to the conductor track structure (131) .

Measuring a current flow through at least one connecting line (471) connected to a sensor electrode (261, 461, 561) and

• Detecting a local stress state in at least a partial area of the conductor track structure (131).

15. The method of claim 14, wherein the conductor track structure (131) is scanned by a grid-shaped movement of the sensor element (150, 250, 350, 450, 550, 650).

16. The method according to any one of claims 13 to 14, wherein between the sensor electrodes (261, 461, 561) and the conductor track structure (131) an amplitude-modulated voltage is applied.

17. Manufacturing method for at least one sensor element (150, 250, 350, 450, 550, 650) for the inspection of a on a flat support (130) formed conductor track structure (131), in particular for contactless inspection of an on a trace matrix (131) formed of a flat panel substrate (130), the manufacturing method comprising the following steps:

Generating at least one trench structure (391) in a starting substrate (390) such that in the starting substrate

(390) a raised upper surface region (392) and a recessed lower surface region (391) are formed, which are interconnected via a transition intermediate region (393), • forming the plurality of sensor electrodes (261, 461, 561) on the upper surface region (392)

Forming the plurality of connection lines (471), each sensor electrode (261, 461, 561) being associated with a connection line (471) extending from the respective sensor electrode (261, 461, 561) to the recessed lower surface area (391), and

Singulating the starting substrate (390) such that at least one sensor element (150, 250, 350, 450, 550, 650) is cut out according to one of claims 1 to 10, wherein - the raised upper portion (260, 360, 460, 560 , 660) of the sensor element (150, 250, 350, 450, 550, 650) is associated with the raised upper surface area (392) of the starting substrate (390),

- the recessed lower portion (280, 380, 480, 580, 680) of the sensor element (150, 250, 350, 450, 550, 650) is associated with the recessed lower surface area (391) of the starting substrate (390) and

- The transition region (270, 370, 470, 570, 670) of the sensor element (150, 250, 350, 450, 550, 650) is associated with the transition intermediate region (393) of the starting substrate.

The manufacturing method according to claim 17, further comprising the step of: forming lateral shields (475) extending from the raised upper surface portion (392) to the recessed lower surface portion (391); in each case a lateral shield (475) is arranged next to a connecting line (471).

19. The manufacturing method according to claim 18, additionally comprising the steps

Applying a first metallization layer and exposing the connection lines,

Application of an insulation layer,

Exposing the sensor electrodes (261, 461, 561) and the lateral shields (475) from the insulating layer,

Depositing a second metallization layer (578) such that the lateral shields (475) and the second metallization layer (578) are electrically conductively connected to each other, and exposing the sensor electrodes (261, 461, 561) from the second metallization layer (578).

The manufacturing method according to any one of claims 17 to 19, further comprising the step of: contacting the connection lines (471) with a flexible circuit board (685).

21. A manufacturing method according to any one of claims 17 to 20, wherein a plurality of sensor elements (150, 250, 350, 450, 550, 650) to be manufactured are placed in the starting substrate (390)

- Some sensor elements (150, 250, 350, 450, 550, 650) adjacent to each other in a row parallel to a longitudinal axis of the trench structure (391) are arranged and / or that

- Some sensor elements (150, 250, 350, 450, 550, 650) with respect to a longitudinal axis of the trench structure (391) are arranged opposite each other on different sides.